Aluminum windows are generally formed by joining together a plurality of separate frame extrusions. Joining the frame extrusions together, i.e., coping, typically includes mitering two adjoining surfaces at right angles, i.e., 90 degrees. This method provides relatively few bearing surfaces that can be sealed to prevent water penetration or leakage into a window assembly. Both interior and exterior joints—but primarily exterior joints—are water infiltration points. Manufacturers of windows seek to eliminate water infiltration.
Gaskets and sealants have been applied to coped corners in a variety of methods and configurations in an attempt to seal the joints and prevent water from leaking into the finished window assembly. Sealants, such as silicone-based compounds or urethane-based compounds, are ordinarily manually applied, subjecting the process to human error. There is a risk of applying insufficient sealant or misapplying sealant. Gaskets are subject to similar problems, in that they are ordinarily manually applied. Misapplied gaskets can be tom by corners of the aluminum extrusions.
A corner key forms a corner joint and connects and aligns adjoining frame members. Conventional corner keys include those described in U.S. Pat. No. 6,067,760 to Nowell and U.S. Pat. No. 6,073,412 to Verch. Corner keys have been used in manufacturing aluminum windows to reduce manufacturing time. Known corner keys are generally hollow and injected with a sealant to retain the adjoining extrusions together. Methods used to inject the sealant into the corner key ordinarily require that at least one aluminum extrusion be pierced. The pierced aluminum extrusion is then manually sealed, usually with a gasket or another sealant. Over time or with handling of the window, the structural integrity of the gasket or seal can degrade or be compromised, which can create an access point for water to leak into the window.
What is needed are products and processes to reduce the susceptibility of a window to water leakage.